1. Field of the Invention
The present invention relates to a contact structure for inspection of electrical characteristics of an object to be inspected.
2. Description of the Related Art
Inspection of electrical characteristics of an electronic circuit, such as an IC, LSI, or the like, formed on, for example, a semiconductor wafer (hereinafter, referred to as a wafer) is performed by bringing a plurality of probes into contact with electrodes of the electronic circuit and making each of the probes apply an electrical signal for inspection to a corresponding electrode. The plurality of probes are formed of a metal material, for example, nickel or the like, and are inserted into and supported by a probe supporting plate. A plurality of through-holes into which the plurality of probes are to be inserted are formed in the probe supporting plate. Then, in order to appropriately perform the inspection, the probe supporting plate which supports the probes is formed of an insulating material that does not affect the electrical signals of the probes, for example, ceramic or the like.
In the formation of the plurality of through-holes in the probe supporting plate formed of ceramic or the like, all of the through-holes are formed by, for example, mechanical machining.
However, recently, as a pattern of an electronic circuit becomes finer, electrodes become finer, and distances between the electrodes become smaller. Therefore, probes which are to be brought into contact with the electrodes are being required to become finer and have a narrower pitch. That is, a plurality of fine through-holes need to be formed in a probe supporting plate. Accordingly, if all of the through-holes are formed by mechanical machining as described above, it takes a lot of time to manufacture the probe supporting plate. Also, since the number of processes for manufacturing the probe supporting plate is increased, manufacturing costs are also increased.
Accordingly, a probe supporting plate having a structure in which a plurality of thin metal plates are laminated is suggested in a conventional art. In this case, a plurality of through-holes are formed in each of the thin metal plates by performing etching or the like on each of the thin metal plates. Next, the plurality of thin metal plates are laminated to form the plurality of through-holes in the probe supporting plate (Patent Document 1: WO 99/04274 International Patent Publication).
However, recently, since the diameter of a wafer becomes larger and also the demand for a test for inspecting the entire wafer at one time, a so-called full wafer test, is increasing, a diameter of a probe supporting plate also becomes larger. In this situation, if the probe supporting plate is configured by laminating a plurality of thin metal plates as in a conventional art, the mass of the entire probe supporting plate is increased due to the high specific gravity of the thin metal plates. Accordingly, it becomes difficult to handle the probe supporting plate.
The present invention is proposed considering the aforementioned state of art. According to the invention it may be obtained to efficiently form a plurality of through-holes in a probe supporting plate while reducing the mass of the probe supporting plate.